League One or League 1 may refer to:

Association football

EFL League One, the third tier of football in England.

China League One, the second tier of football in China

K League 1, the top-tier football in South Korea

Lao League 1

League1 British Columbia, semi-professional regional league in Canada

League1 Ontario, semi-professional regional league in Canada

League1 Ontario (women), semi-professional women's regional league in Canada

Scottish League One, the third tier of football in Scotland

Thai League 1, the top tier of football in Thailand

USL League One, a third-tier soccer league in the United States

Rugby

RFL League One, the third tier of rugby league in Europe

National League 1, the third tier of rugby union in England